Acrylate color-stabilized phenolic bound abrasive products and methods for making same

ABSTRACT

Described is a color-stable abrasive article that includes a phenolic resin binder; a color stabilizer, a colorant, and abrasive grains. The color stabilizer includes at least one acrylate. The color-stable abrasive article is formed by a method including the steps of blending a resole and a color stabilizer to form a resole composition; contacting a plurality of abrasive particles with the resole composition; and curing the resole composition to produce the color-stable abrasive article. Thus provided are color stabilized phenolic bound abrasives and a method for making such abrasives that resist color change over time and upon exposure to high temperature and maintain the mechanical strength of a phenolic resin.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.61/199,471, filed on Nov. 17, 2008. The entire teachings of the aboveapplication are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The term “phenolic resin” describes a wide variety of resin productsthat result from the reaction product of phenols and aldehydes. Phenolsreact with formaldehydes under both acidic and basic conditions. If abased-catalyzed mixture of a phenol and a formaldehyde contains one ormore moles of formaldehyde per moles of phenol, it will produce athermosetting (one-step) resin, or “resole.” Common base compoundsemployed as catalysts for resole resins include the hydroxides of alkalimetals, such as sodium, potassium, or lithium. While alkali metalhydroxide-catalyzed phenolic resins are commercially useful, they havean undesirable tendency to darken as they age, are heated or otherwisecured. The extent of darkening is known to be dependent on the curing oruse temperature of the resin and the time of exposure to suchtemperature.

Alkali metal hydroxide-catalyzed phenolic resins are commonly used as acomponent of the bond system of abrasive products, such as coated,bonded, and three-dimensional, low density abrasive products. The resindarkening problem is particularly pronounced in coated abrasive andthree-dimensional, low density abrasive products because of the morevisible presence of the bond system. Also, since the darkening increaseswith temperature and exposure time, any variation in the temperatureprofile of the product results in color variation within the productitself. Color variation is particularly noticeable for light-coloredproducts, causing such products to be unacceptable for aesthetic orother reasons.

Furthermore, abrasive bond systems may comprise colorants to identifythe manufacturer, type of product, application, etc. The darkening ofthe resin can interfere with the desired coloration, causing the finalproduct to have a different color from the colorant added. For example,a resin that normally turns yellow after curing will yield a greencolored product when combined with a blue dye or pigment. On the otherhand, if the same yellow resin is combined with a green dye or pigment,the resin will typically result in simply another shade of green.

One known method for imparting color stability in phenolic resolesinclude adding melamine formaldehyde resin into the formulation. Whilethis achieves color stability, it also imparts brittleness, takes longerto cure, and results in mechanical weakness and therefore reducedgrinding performance in the finished product.

Another proposed method includes the addition of an ammonium based saltto the phenolic resole. However, this method is not sufficientlyeffective in stabilizing the color of phenolic resin products havingcertain colorants, such as light blue and orange pigments or dyes.

What is needed is an effective phenolic resin color-stabilizer thatreduces the aforementioned problems without imparting undesirableproperties in the finished product.

SUMMARY OF THE INVENTION

In one aspect, the present invention is directed to a color-stableabrasive article that includes a phenolic resin binder; a colorstabilizer, a colorant, and abrasive grains. The color stabilizerincludes at least one acrylate.

In another aspect, the present invention is directed to a method ofmaking a color-stable abrasive article including the steps of blending aresole and a color stabilizer to form a resole composition; contacting aplurality of abrasive particles with the resole composition; and curingthe resole composition to produce the color-stable abrasive article. Thecolor stabilizer comprises at least one acrylate.

In yet another aspect, the present invention is directed to a method forabrading a work surface including applying color-stable abrasive articleto a work surface in an abrading motion to remove a portion of the worksurface. The abrasive product includes a binder having a phenolic resin,a color-stabilizer that includes at least one acrylate, and abrasivegrains.

Thus provided are color stabilized phenolic bound abrasives and a methodfor making such abrasives that resist color change over time and uponexposure to high temperature and maintain the mechanical strength of aphenolic resin.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particulardescription of example embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingembodiments of the present invention.

FIG. 1 is a schematic representation of a cross-sectional view of oneembodiment of coated abrasive tools of the invention.

FIG. 2 is a schematic representation of a cross-sectional view ofanother embodiment of coated abrasive tools of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The teachings of all patents, published applications and referencescited herein are incorporated by reference in their entirety. Inparticular, U.S. Ser. No. 61/199,472, entitled, “Carboxylic Acid EsterColor-stabilized Phenolic Bound Abrasive Products and Methods for MakingSame,” of Everts, et al., which application is filed concurrentlyherewith, is incorporated by reference herein in its entirety.

The present invention relates to abrasive articles which include aphenolic resin binder that is color-stabilized by acrylates. Thecolor-stabilized abrasive article further includes a colorant andabrasive grains. As used herein, an abrasive article or resin isconsidered to be “color-stable” if it has essentially the same colorafter about 8 hours of curing at about 235° F. as it does after about 2hours of curing at about 235° F.

The term “phenolic resin” refers to any resinous reaction product of aphenol, such as phenol, resorcinol, alkyl-substituted phenol such ascresol, xylenol, p-tert-butylphenol, and p-phenylphenol and the like,with an aldehyde, such as formaldehyde, acetaldehyde and furfuraldehyde,and the like. “Color-stabilized alkali metal hydroxide catalyzedphenolic resin” refers to a cured alkali metal hydroxide phenolic resinwhich is color-stabilized by a color stabilizing agent.

The abrasive products are characterized by having a phenolic resinbinder, one or more acrylate color-stabilizers, one or more optionalcolorants, abrasive grains, a support member or backing, and can furtherinclude curing agents, non-reactive thermoplastic resins, fillers,grinding aids, and other additives.

Structure and Methods of Making the Abrasive Article

In one embodiment, the color-stable abrasive article includes a phenolicresin binder, a color stabilizer, and an abrasive material. Thecolor-stable abrasive article can be either a bonded, structured, orcoated abrasive.

Coated abrasive tools of the invention can include a substrate, anabrasive material and at least one phenolic resin binder to hold theabrasive material to the substrate. As used herein, the term “coatedabrasive tool” encompasses a nonwoven abrasive tool. The abrasivematerial, such as abrasive grains, particles or agglomerate thereof, canbe present in one layer (e.g., resin-abrasive layer) or in two layers(e.g., make coat and size coat) of the coated abrasive tools. Examplesof such coated abrasive tools that can be made by the methods of theinvention are shown in FIGS. 1 and 2. Referring to FIG. 1, in coatedabrasive tool 10, substrate 12 is treated with optional backsize coat 16and optional presize coat 18. Overlaying the optional presize coat 18 ismake coat 20 to which abrasive material 14, such as abrasive grains orparticles, are applied. Size coat 22 is optionally applied over makecoat 20 and abrasive material 14. Overlaying size coat 22 is optionalsupersize coat 24. Depending upon their specific applications, coatedabrasive tool 10 may or may not include backsize coat 16 and/or presizecoat 18. Also, depending upon their specific applications, coatedabrasive tool 10 may or may not include size coat 22 and/or supersizecoat 24. Shown in FIG. 2 is an example of coated abrasive tools that canbe formed by the methods of the invention, where coated abrasive tool 30includes a single binder/abrasive layer 32 of an abrasive material andadhesive(s) and optional backsize coat 16. Optionally, presize coat 18,size coat 22 and supersize coat 24, as shown in FIG. 1, can be includedin coated abrasive tool 30. The coated abrasive article can include acolor stable phenolic resin binder in at least one layer selected fromthe group consisting of a binder-abrasive layer, a backsize coat, apresize coat, a make coat, a size coat, and a supersize coat.

In embodiments including size coats and supersize coats, such as thatshown in FIG. 1, abrasive materials can be applied separately bygravity, electrostatic deposition, air stream, or as a slurry togetherwith the polyurethane adhesive compositions. The make coat 20 adheresthe abrasive material to the surface of the substrate, and can be formedby impregnating the support substrate with the phenolic resin binderwithout abrasive grains.

In the embodiment of FIG. 2, the support substrate may be impregnatedwith a resin/abrasive slurry that includes an abrasive material and aresin composition including a phenolic resin binder and acolor-stabilizer, to form a binder/abrasive layer 32.

In one embodiment, a method of making a color-stable abrasive articleincludes: blending a resole and a color-stabilizer comprising at leastone acrylate to form a resole composition; contacting a plurality ofabrasive particles with the resole composition; and curing the resolecomposition to produce the color-stable abrasive product. In addition tothe coated abrasives described above, color-stable abrasive articlesformed by this method include, for example, structured abrasives andbonded abrasives.

With respect to structured abrasives, the article is formed by any ofthose techniques known in the art in which abrasive structures areshaped prior to curing. Such techniques include, for example, embossingtechniques. In one embodiment, for instance, a mixture of phenolic resinbinder, acrylate color-stabilizer, optional colorants, and abrasivegrains, can be contacted with a backing and a production tool whereinthe mixture adheres to one surface of the backing. Abrasive structuresare thus formed that have the shape of an inside surface of theproduction tool.

A bonded abrasive article can be formed by preparing an agglomerate thatincludes the phenolic resin binder, acrylate color-stabilizer, optionalcolorants, and abrasive grains. The agglomerate is then shaped using anyof the techniques known in the art for preparing a bonded abrasive.Suitable techniques for preparing bonded abrasives are further describedin, for example, U.S. Pat. Nos. 5,738,696 of Wu; 5,738,697 of Wu, etal.; and 6,679,758 of Bright, et al.; and U.S. Patent Publication No.2003/0192258 A1 of Simon, the entire contents of each of which areincorporated herein by reference.

A work surface is abraded by applying the color-stable abrasive articleto a work surface in an abrading motion to remove a portion of the worksurface.

Phenolic Resin Binder

Typical phenolic resins employed in the present invention are resoles,which result from the alkali metal hydroxide catalyzed reaction ofphenol and formaldehyde in a mole ratio of phenol:formaldehyde of about1:1 to about 1:3 moles and a mole ratio of phenol:alkali metal hydroxideof about 1:1 to about 100:1. The color of such resole, or base-catalyzedphenolic resin is stabilized by the addition of one or more acrylates.Durez Varcum Resin No. 94908, manufactured by Durez Corporation is oneexample of a water-based, single-staged liquid phenolic resin that canbe used as the binder. Other examples are provided in Table 1 below.

TABLE 1 Phenolic Resin Binders Resin Code Vendor HRJ15881 SI HRJ15993 SIHRJ16051 SI 94-908 Durez 13537 Hexion 29-777 Durez 29-778 Durez 43575Durez  5408 GP  5410 GP 29-382 Durez 80-5080A Ardin 80-5078 Ardin80-5046A Ardin

Color-Stabilizer

The color-stabilizers employed in the present invention includeacrylates. Examples of acrylates include ethyl acrylate, epoxy acrylate,pentacrylate, and trimethylolpropane triacrylate (TMPTA). Depending onthe presence of other components in the formulation, the optimal amountof acrylate present in the binder formulation can vary. In certainembodiments, the percentage of the acrylate resin can be between about2% and about 60% by weight of the phenolic resin, between about 5% andabout 60% by weight of the phenolic resin, between about 10% and about60% by weight of the phenolic resin, or between about 7% and about 15%by weight of the phenolic resin.

For example, in embodiments where the phenolic resin formulationincludes peroxide or an ultraviolet photoinitiator, as described furtherbelow, the acrylate is preferably present in a larger percentage, suchas between about 10% and about 60% by weight. In embodiments where theacrylate resin can react with the phenolic resin, the percentage ofacrylate can be between about 5% and about 60% by weight.

In one embodiment, the color-stabilizer is one or more acrylate resinshaving high a functionality of acrylic groups, such as pentacrylate andtrimethylolpropane triacrylate (TMPTA). Other suitable resins includemethyl lactate, ethyl lactate, n-propyl lactate, butyl lactate, epoxyacrylate, and 2-ethylhexyl lactate.

In another embodiment, the one or more acrylate resin is a water solubleresin, such as ethoxylated TMPTA. As described herein, the term “watersoluble” means completely miscible in water. In yet another embodiment,the one or more acrylate resin is not water soluble. The insolubleacrylate resin can be present in an amount between about 2% and about15% by weight. In some embodiments, the composition further includes aco-solvent, such as glycol. Optionally, vitamins E and C can be addedbetween 1% and 20% by weight of resin.

It is believed that acrylates impart color stability to phenolic resinsby reacting with phenoxy radicals that would otherwise oxidize and formdarkly colored quinine structures. Reactions 1 and 2 represent anexample of the mechanism that is believed to occur when an acrylate isnot present in the phenolic resin, while reaction 3 represents analternative to reaction 2 that occurs when an acrylate is present.

In reaction 1, the phenol ionizes in basic media, forming a phenolateion and a corresponding resonant phenoxy radical structure.

In Reaction 2, the phenoxy radical undergoes rapid oxidation in base toform a darkly colored quinone structure.

In Reaction 3, trimethylolpropanetriacrylate reacts with the phenoxyradical, precluding the formation of the darkly colored quinine moiety,resulting in a color stable resin. Incorporation of the acrylate repeatunit into the phenolic resin network has also shown to impart toughnessto the polymer.

Colorant

The abrasive product can include a colorant, for example, dyes orpigments. Generally, a portion of the colorant can be visible throughthe cured resin. In some embodiments, a portion of the colorant isincluded in the cured resin, in an optional support substrate, and/or ina coating between the optional support substrate and the cured resin. Inparticular embodiments, the colorant can include organic polycyclicdyes, organic monoazo dyes, organic diazo dyes, organometal complexes,inorganic pigments such as metal oxides or complexes. Dyes can beperinone, anthraquinone, azo dye complexes and thioindigoid.

A fluorescent colorant is a dye or pigment containing a fluorescentorganic molecule. Detailed descriptions of fluorescent colorants can befound in Zollinger, H., “Color Chemistry: Synthesis, Properties, andApplications of Organic Dyes and Pigments”, 2^(nd) Ed., VCH, New York,1991, the entire teachings of which are incorporated herein byreference. As used herein, a fluorescent colorant can be, for example, axanthene, thioxanthene, fluorene (e.g., fluoresceins, rhodamines,eosines, phloxines, uranines, succineins, sacchareins, rosamines, andrhodols), napthylamine, naphthylimide, naphtholactam, azalactone,methine, oxazine, thiazine, benzopyran, coumarin, aminoketone,anthraquinone, isoviolanthrone, anthrapyridone, pyranine, pyrazolone,benzothiazene, perylene, or thioindigoid. More preferably, a fluorescentcolorant is selected from the group consisting of xanthenes,thioxanthenes, benzopyrans, coumarins, aminoketones, anthraquinones,isoviolanthrones, anthrapyridones, pyranines, pyrazolones,benzothiazenes, thioindigoids and fluorenes. Most preferably, thefluorescent colorant is a thioxanthene or thioxanthene.

One skilled in the art understands that, for many, commerciallyavailable colorants, the specific chemical structure of individualderivatives within a class, e.g., thioxanthene derivatives, may not bepublicly available. Thus, specific fluorescent colorants are typicallyreferred to by Colour Index (C.I.) name, as defined in “Colour IndexInternational”, 4^(th) Ed. American Association of Textile Chemists andColorists, Research Triangle Park, N.C., 2002. The Colour Index is alsoavailable online at www.colour-index.org. The entire teachings of theColour Index are incorporated herein by reference.

Examples of preferred fluorescent colorants include C.I. Solvent Orange63 (Hostasol Red GG, Hoechst AG, Frankfurt, Germany), C.I. SolventYellow 98 (Hostasol Yellow 3G, Hoechst AG, Frankfurt, Germany), and C.I.Solvent Orange 118 (FL Orange SFR, Keystone Aniline Corporation,Chicago, Ill.).

The amount of colorant that can be employed depends on the particularsof the intended use, the characteristics of the colorant, the othercomponents in the composition, and the like. One skilled in the art willknow how to judge these details to determine the amount of colorant fora particular use. Typically, the amount of colorant will be a weightfraction of the total composition of between about 0.01 and about 2%,more preferably between about 0.05 and about 0.5%, and most preferably,about 0.2%.

In specific embodiments, the colorant is a red, orange, yellow, green,blue, indigo, or violet colorant. In specific embodiments, the colorantis fluorescent, for example, a fluorescent red, fluorescent orange(blaze orange), fluorescent yellow, fluorescent green, or the like.

The colorant can be employed to identify the abrasive product, e.g., forcommercial branding, for usage indication such as wet, dry, wood, metal,or the like, or for identification of grit size, or the like.

Abrasive Grains

Abrasive grains can include of any one or a combination of grains,including, but not limited to, silica, alumina (fused or sintered),zirconia, zirconia/alumina oxides, silicon carbide, garnet, diamond,cubic boron nitride (CBN), silicon nitride, ceria, titanium dioxide,titanium diboride, boron carbide, tin oxide, tungsten carbide, titaniumcarbide, iron oxide, chromia, flint, and emery. For example, theabrasive grains may be selected from a group consisting of silica,alumina, zirconia, silicon carbide, silicon nitride, boron nitride,garnet, diamond, cofused alumina zirconia, ceria, titanium diboride,boron carbide, flint, emery, alumina nitride, and a blend thereof. Insome instances, dense abrasive grains comprised principally ofalpha-alumina and/or gamma alumina can be used.

The abrasive grains can also include abrasive agglomerate grains, alsoknown as agglomerated abrasive grains. Abrasive agglomerate grainsinclude abrasive particles adhered together by a particle bindermaterial. The abrasive particles present in abrasive agglomerate grainscan include one or more of the abrasives known for use in abrasive toolssuch as, for example, silica, alumina (fused or sintered), zirconia,zirconia/alumina oxides, silicon carbide, garnet, diamond, cubic boronnitride (CBN), silicon nitride, ceria, titanium dioxide, titaniumdiboride, boron carbide, tin oxide, tungsten carbide, titanium carbide,iron oxide, chromia, flint, emery, and combinations thereof. Theabrasive particles can be of any size or shape. The abrasive agglomerategrains can be adhered together by a particle binder material such as,for example, a metallic, organic, or vitreous material, or a combinationof such materials. Abrasive agglomerate grains suitable for use in thepresent invention are further described in U.S. Pat. No. 6,797,023, toKnapp, et al., the entire contents of which are incorporated herein byreference.

The abrasive grains can have one or more particular shapes. Example ofsuch particular shapes include rods, triangles, pyramids, cones, solidspheres, hollow spheres and the like. Alternatively, the abrasive grainscan be randomly shaped.

Typically, the abrasive grains have an average grain size not greaterthan 2000 microns such as, for example, not greater than about 1500microns. In another example, the abrasive grain size is not greater thanabout 750 microns, such as not greater than about 350 microns. In someembodiments, the abrasive grain size may be at least 0.1 microns, suchas from about 0.1 microns to about 1500 microns, and, more typically,from about 0.1 microns to about 200 microns or from about 1 micron toabout 100 microns. The grain size of the abrasive grains is typicallyspecified to be the longest dimension of the abrasive grain. Generally,there is a range distribution of grain sizes. In some instances, thegrain size distribution is tightly controlled.

Support Member/Backing

The abrasive articles can include a support member, or backing. Thebacking can be flexible or rigid. The backing can be made of any numberof various materials including those conventionally used as backings inthe manufacture of coated abrasives. Suitable backings can includepolymeric films (for example, a primed film), such as polyolefin films(e.g., polypropylene including biaxially oriented polypropylene),polyester films (e.g., polyethylene terephthalate), polyamide films, orcellulose ester films; metal foils; meshes; foams (e.g., natural spongematerial or polyurethane foam); cloth (e.g., woven, non-woven, fleeced,stitch bonded, or quilted, or cloth made from fibers or yams comprisingpolyester, nylon, silk, cotton, poly-cotton or rayon); paper; vulcanizedpaper; vulcanized rubber; vulcanized fiber; nonwoven materials; atreated backing thereof; or any combination thereof.

The backing can have at least one of a saturant, a presize layer or abacksize layer. The purpose of these layers typically is to seal thebacking or to protect yarn or fibers in the backing. If the backing is acloth material, at least one of these layers typically is used. Theaddition of the presize layer or backsize layer may additionally resultin a “smoother” surface on either the front or the back side of thebacking. Other optional layers known in the art can also be used (forexample, a tie layer; see U.S. Pat. No. 5,700,302 of Stoetzel, et al.,the entire contents of which are incorporated herein by reference).

In some embodiments, the abrasive articles are intended for use as finegrinding materials and hence a very smooth surface can be preferred.Examples of such smooth surfaced backings include finely calenderedpapers, plastic films or fabrics with smooth surface coatings.

The backing can have antistatic properties. The addition of anantistatic material can reduce the tendency of the abrasive article toaccumulate static electricity when sanding wood or wood-like materials.Additional details regarding antistatic backings and backing treatmentscan be found in, for example, U.S. Pat. Nos. 5,108,463 of Buchanan, etal.; 5,137,542 of Buchanan, et al.; 5,328,716 of Buchanan; and 5,560,753of Buchanan, et al., the entire contents of which are incorporatedherein by reference.

The backing can include a fibrous reinforced thermoplastic such asdescribed, for example, in U.S. Pat. No. 5,417,726 of Stout, et al., oran endless spliceless belt, as described, for example, in U.S. Pat. No.5,573,619 of Benedict, et al., the entire contents of which areincorporated herein by reference. Likewise, the backing can include apolymeric substrate having hooking stems projecting therefrom such asthat described, for example, in U.S. Pat. No. 5,505,747 of Chesley, etal., the entire contents of which are incorporated herein by reference.Similarly, the backing can include a loop fabric such as that described,for example, in U.S. Pat. No. 5,565,011 of Follett, et al., the entirecontents of which are incorporated herein by reference.

Other Components

The abrasive articles of the present invention can also include variousother components, such as curing additives, non-reactive thermoplasticresins, fillers, grinding aids; and other additives.

In some embodiments, the abrasive article includes a curing additive,such as a photoinitiator, which generates free radicals when exposed toradiation, e.g., UV radiation. Free-radical generators can includeorganic peroxides, azo compounds, quinones, benzophenones, nitrosocompounds, acryl halides, hydrozones, mercapto compounds, pyryliumcompounds, triacrylimidazoles, bisimidazoles, chloroalkyltriazines,benzoin ethers, benzil ketals, thioxanthones and acetophenones,including derivatives of such compounds. Among these the most commonlyemployed photoinitiators are the benzil ketals such as2,2-dimethoxy-2-phenyl acetophenone (available from Ciba SpecialtyChemicals under the trademark IRGACURE® 651) and acetophenonederivatives such as 2,2-diethoxyacetophenone (“DEAP”, which iscommercially available from First Chemical Corporation),2-hydroxy-2-methyl-1-phenyl-propan-1-one (“HMPP,” which is commerciallyavailable from Ciba Specialty Chemicals under the trademark DAROCUR®1173), 2-benzyl-2-N,N-dimethylamino-1-(4-morpholinophenyl)-1-butanone,(which is commercially available from Ciba Specialty Chemicals under thetrademark IRGACURE® 369); and2-methyl-1-(4-(methylthio)phenyl)-2-morpholinopropan-1-one, (availablefrom Ciba Specialty Chemicals under the trademark IRGACURE® 907).

The abrasive articles can include a non-reactive thermoplastic resinsuch as, for example, polypropylene glycol, polyethylene glycol, andpolyoxypropylene-polyoxyethene block copolymer.

Fillers include organic fillers, inorganic fillers, and nano-fillers.Examples of suitable fillers include, but are not limited to, metalcarbonates such as calcium carbonate and sodium carbonate; silicas suchas quartz, glass beads, glass bubbles; silicates such as talc, clays,calcium metasilicate; metal sulfate such as barium sulfate, calciumsulfate, aluminum sulfate; metal oxides such as calcium oxide, aluminumoxide; aluminum trihydrate, and combinations thereof.

The abrasive articles can include a grinding aid to increase thegrinding efficiency and cut rate. Useful grinding aids can be inorganic,such as halide salts, e.g., sodium cryolite and potassiumtetrafluoroborate; or organic based, such as chlorinated waxes, e.g.,polyvinyl chloride. In one particular embodiment, the abrasive articleincludes cryolite and potassium tetrafluoroborate with particle sizeranging from about 1 micron to about 80 microns, most typically fromabout 5 microns to about 30 microns. The concentration of grinding aidin a make coat is generally not greater than about 50 wt %, for example,the concentration of grinding aid is often about 0.1 wt % to 50 wt %,and most typically about 10 wt % to 30 wt % (all wt % based on make coatweight including abrasive grains).

Examples of additional additives include coupling agents, such as silanecoupling agents, e.g., A-174 and A-1100 available from Osi Specialties,Inc., titanate, and zircoalurminates; anti-static agents, such asgraphite, carbon black, and the like; suspending agent, such as fumedsilica, e.g., Cab-O-Sil M5, Aerosil 200; anti-loading agents such aszinc stearate and calcium stearate; lubricants such as wax, PTFE powder,polyethylene glycol, polypropylene glycol, and polysiloxanes; wettingagents; pigments; dispersants; and defoamers.

EXEMPLIFICATION

The invention will now be further and specifically described by thefollowing examples which are not intended to be limiting.

Example 1

Four phenolic resin compositions were formulated. Each compositioncontained the components shown in Table 2.

TABLE 2 Material LBS Percentage Resin PF Prefere 80-5080A 21.0 20.9%Pigment Elcom Orange SK 2.8 2.8% Nalco 2341 Defoamer 0.1 0.1% SolmadDaxad 11 1.7 1.7% Solmod Cab-o-sil 0.1 0.1% Filler Solvay Type A KBF464.5 64.3% TMPTA 2.3 2.3% Water 7.9 7.9% 100.3 100.0%

In addition, formulations 2-4 each contained the same amounts of adifferent acrylate. Table 3 below indicates the amount of acrylatepresent in each of the formulations.

TABLE 3 Amount of Color after curing Type of acrylate added to acrylatefor 10 hrs @ Trial No. phenolic resin formulation present 250° F. 1 N/A0% black 2 Epoxy Acrylate (Ebecryl 10% red 3700) 3 Pentacrylate 10%light brown-yellow 4 TMPTA 10% light brown-yellow

The table shows that the compositions containing the acrylates wereresistant to darkening upon exposure to heat during curing. Inparticular, pentacrylate and TMPTA were found to be the most effectivein stabilizing the color of the phenolic resin.

EQUIVALENTS

While this invention has been particularly shown and described withreferences to example embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims.

1. A color-stable abrasive article, comprising: a) a binder comprising a phenolic resin; b) a color-stabilizer that includes at least one acrylate; and c) abrasive grains.
 2. The color-stable abrasive article of claim 1, wherein the phenolic resin is a resole.
 3. The color-stable abrasive article of claim 1, wherein the color-stabilizer is present in an amount between about 2% and about 60% by weight.
 4. The color-stable abrasive article of claim 1, wherein the color-stabilizer is present in an amount between about 7% and about 15% by weight.
 5. The color-stable abrasive article of claim 1, further comprising a support member.
 6. The color-stable abrasive article of claim 1, wherein the color-stabilizer is an acrylate selected from the group consisting of ethyl acrylate, epoxy acrylate, pentacrylate, and trimethylolpropane triacrylate (TMPTA).
 7. The color-stable abrasive article of claim 1, wherein the color-stabilizer includes a water soluble acrylate resin.
 8. The color-stable abrasive article of claim 7, wherein the water soluble acrylate resin is ethoxylated trimethylolpropane triacrylate.
 9. The color-stable abrasive article of claim 7, further comprising a co-solvent.
 10. The color-stable abrasive article of claim 9, wherein the co-solvent is glycol.
 11. The color-stable abrasive article of claim 1, wherein the color-stabilizer includes a water insoluble acrylate resin.
 12. The color-stable abrasive article of claim 11, wherein the water insoluble acrylate resin is present in an amount between about 2% and about 15% by weight.
 13. The color-stable abrasive article of claim 6, further comprising a curing additive.
 14. The color-stable abrasive article of claim 13, wherein the curing additive includes one or more additives selected from the group of peroxide and a UV photo-initiator.
 15. The color-stable abrasive article of claim 13, wherein the acrylate is present in an amount between about 5% and about 60% by weight.
 16. The color-stable abrasive article of claim 13, wherein the acrylate is present in an amount between about 10% and about 60% by weight.
 17. The color-stable abrasive article of claim 6, wherein the acrylate resin is capable of reacting with the phenolic resin.
 18. The color-stable abrasive article of claim 1, having no visually perceptible color change after about 8 hours of curing at about 235° F. relative to the same article after about 2 hours of curing at about 235° F.
 19. The color-stable abrasive article of claim 1, further comprising a colorant.
 20. The color-stable abrasive article of claim 1, wherein the article is a bonded, structured, or coated abrasive article.
 21. The color-stable abrasive article of claim 20, wherein the phenolic resin binder and color stabilizer are present in at least one layer selected from the group consisting of a binder-abrasive layer, a backsize coat, a presize coat, a make coat, a size coat, and a supersize coat.
 22. A method of making a color-stable abrasive article, comprising the steps of: a) blending a resole and a color-stabilizer comprising at least one acrylate to form a resole composition; b) contacting a plurality of abrasive particles with the resole composition; and c) curing the resole composition to produce the color-stable abrasive article.
 23. A method for abrading a work surface, comprising applying color-stable abrasive article to a work surface in an abrading motion to remove a portion of the work surface, the abrasive product including: a) a binder comprising a phenolic resin; b) a color-stabilizer that includes at least one acrylate; and c) abrasive grains. 